What is Glucosamine?

Sherry Holetzky

Glucosamine is an amino sugar compound produced by the body. Though it is common in the liver and kidneys, it is most often found in cartilage. Glucosamine is derived from glucose molecules and is believed to aid in repairing damaged cartilage, building new cartilage, cushioning joints, relieving pain, and reducing inflammation.

People with diabetes should be especially careful when taking glucosamine.
People with diabetes should be especially careful when taking glucosamine.

Glucosamine is also the name given to the dietary supplement created through extracting amino sugars from the tissues of shellfish such as crab and lobster. There are also glucosamine sulfates, which are synthetically produced salts derived from naturally occurring glucosamine. These salts are sometimes combined with chondroitin sulfates to aid in the relief of arthritis and other painful conditions affecting the joints, ligaments, and tendons. Sulfates may not be as potent as extracted glucosamine.

Glucosamine is produced in the liver.
Glucosamine is produced in the liver.

Current data indicates that patients who take these supplements experience pain relief and reduced inflammation at about the same level as that which is achieved through taking non-steroidal anti-inflammatory medications, or NSAIDS, such as aspirin and ibuprofen. There is also a liquid form of this supplement available for those whom have difficulty swallowing pills.

Glucosamine supplements are often taken to help relieve joint pain.
Glucosamine supplements are often taken to help relieve joint pain.

Although glucosamine may have fewer side effects than NSAIDS for most patients, people who suffer from diabetes should be especially careful when taking this supplement since it is derived from glucose. It is wise to speak to a doctor before use and to check blood sugar more frequently during use.

Glucosamine is a dietary supplement that can be made by extracting amino sugars from the tissues of shellfish such as crab.
Glucosamine is a dietary supplement that can be made by extracting amino sugars from the tissues of shellfish such as crab.

People who are allergic to shellfish should take care when using this product, although shellfish allergies usually indicate that a person is allergic to the proteins found in shellfish. The substance is extracted from a carbohydrate rather than a protein, but allergy sufferers should still consult with a health care provider before taking it, as should pregnant and nursing women. This supplement is not recommended for children.

Research suggests that glucosamine supplements can help alleviate osteoarthritis of the knee.
Research suggests that glucosamine supplements can help alleviate osteoarthritis of the knee.

Glucosamine is labeled as a food supplement and therefore the amount and purity of glucosamine in such products is not regulated by the Food and Drug Administration. Before choosing a supplement, compare the concentration in similar products or ask your pharmacist to assist you in selecting a supplement. Choose a well-known, well-established brand name that guarantees its products.

Always consult with your health care provider before beginning a supplement regimen, and make sure the supplement will not adversely interact with current medications.

Glucosamine sulfates can be used to relieve the symptoms of arthritis.
Glucosamine sulfates can be used to relieve the symptoms of arthritis.

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Discussion Comments


I'm so glad I read the above comments. I recently adopted a 10-year-old lab retriever. I am familiar with joint issues, arthritis, spine issues, etc. from my previous shepherd mix. I thought nothing about starting Charlie on glucosamine because it is so common with people and dogs. But I gave Charlie the three pills yesterday for his size and within six hours he had diarrhea. All day today he hasn't been eating or drinking and has had diarrhea. He was trying to eat grass and he did vomit a little, mostly clear liquid. I am letting him sleep and take it easy which is what he wants to do. I am stopping the glucosamine immediately. I will find something else for him. Maybe just some type of aspirin. Thank you to the people above for posting. I have posted my experience in the hope that it also helps someone.


Bottom line: Do your own research or talk to a pharmacist who is willing to do the research for you. I glanced at this site while doing research (I'm having difficulty finding synthetic glucosamine in articles) and the fact that there isn't even a reference on this page should be alarming to anyone.

Diabetics should be careful taking this because it is related to Glucose (it is an amino derivative, hence Glucosamine). To be fair, studies are all over the place when it comes to glucosamine and chondroiton, and this page could just as easily site resources to support their argument as I could to support mine. Bottom line, it's effectiveness is a topic of debate and ongoing research. The RCT's I have read recently show that placebo was almost as effective in improving pain symptoms as expressed by the patient.

Also, for those who believe they have lost their dogs to this supplement, I don't know whether this would be the cause but I want to remind everyone that a vet should be about the only person to recommend something for your pet. As for us humans, please see your local pharmacist or family physician in addition to your own research. --A Pharmacy Student


My dog has been on Missing Link for Joint Health which has glucosamine in it and she is thriving. Her hips are much better and she's more playful. Perhaps the dosage has been incorrect for some of your pets and it might be better to have let them taken it in conjunction with other healing elements.


I think glucosamine killed my dog too. I've been searching the net and am seeing a recurrence of quite a few dogs getting ill from glucosamine supplements. My vet said it was safe when I told him it was the one supplement I was giving him. If your dog gets sick one time, please stop! Some dogs are very sensitive to it. Beware!


I had very bad joint pain in my hands for over five years now and I'm only 25. I have been taking Glucosamine Chondroitin and MSM pills for a about three weeks now which I bought from Vitacost online. It has worked perfect for me, my pain is gone and I have very little stiffness. I have also given some to my mother who is over 50 to start taking as her joints were hurting her all over her body, and she can tell the difference as well. The brand I bought is NSI.

I would pay a thousand dollars for these pills because I have tried everything else with no results. hope this helps someone!


If glucosamine sulfate is a salt, why can diabetics not take it?


This is all very confusing. This page explains what glucosamine is and its benefits are; however, I read another article explaining that glucosamine was proven not to work at all by a study carried out by University of Utah researchers (if I'm not mistaken). Does it work or not? And if it doesn't, why does this page still show this misleading information?


Well, I am no. 6. My dog died yesterday. One day after I posted my question. I will never give a dog Glucosamine again!


I know the Glucosamine is causing the same symptoms in my dog. She has arthritis and the vet told me to give her 500 mg of Glucosamine a day. I could only get 250 mg in her each day. She started getting very sick to her stomach. (loose stools and vomiting) Her legs got worse. More stiff and weak. The vet gave her Prednisone and it helped. I thought I could give her the Glucosamine again. One dose and she is so sick again, she can't stop vomiting. She can hardly walk at all. My vet said it is very rare, but she can't tolerate it. It has been two days, and she is not getting better. Does anyone know how long it stays in the system? Thanks


You need to take your dog to a veterinarian immediately- it seems extremely unlikely all of those symptoms, especially soreness and inability to walk, are due to a megadose of glucosamine.-vet tech jon


Glucosamine overdose will typically cause

mild gastrointestinal problems in some sensitive individuals, but the side-effects are reversible and will disappear upon discontinuing use. People with peptic ulcers and those taking diuretics are more likely to experience gastrointestinal discomfort than others. People who are allergic to shellfish (it is derived from the shells) should not take glucosamine supplements derived from shrimp, crabs or lobsters. You can find synthetic glucosamine if you have allergies.



Though I don't know anything about harmful side effects of too much glucosamine, I highly recommend taking your dog to the vet. With symptoms like that, I wouldn't spend too much time wondering...

Best of luck!


okay the pharmasisit in my town told me to give my dog only one pill a day, just regular glucosamine, now what i am wondering, is how much would it take to make a dog sick, my dog has been really sick and i think that my foster kid could be giving her too much, how many pills do you think it would take, and how long do you think it could take for her to pass on, if this kid is killing my dog i want to be able to do somehting about it, i have hid the glucosamine.. some of the side effects that she has been having are puking, diarea, soreness, not being able to climb stairs, and not being able to get up off of her belly. thank you soo much for your time!!

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